Speech Dereverberation via Sub-band Implementation of Subspace Methods

A novel approach for sub-band based multi-microphone speech dereverberation is presented. In recent contribution a method utilizing the null subspace of the spatial-temporal correlation matrix of the received signals (obtained by the generalized eigenvalue decomposition (GEVD) procedure). The desired acoustic transfer functions (ATF-s) are shown to be embedded in these generalized eigenvectors. The special Silvester structure of the filtering matrix, related to this subspace, was exploited for deriving a total least squares (TLS) estimate for the ATF-s. The high sensitivity of the GEVD procedure to noise, especially when the involved ATF-s are very long, and the wide dynamic range of the speech signal, make the proposed method problematic in realistic scenarios. In this contribution we suggest to incorporate the TLS subspace method into a sub-band structure. The novel method proves to be efficient, although some new problems arise and other remain open. A preliminary experimental study supports the potential of the proposed method.